Vus from hadronic ι decays

We study the reliability of extractions of vertical bar V-us vertical bar based on flavor-breaking hadronic tau decay sum rules. The "(0, 0) spectral weight", proposed previously as a favorable candidate for this extraction, is shown to produce results having poor stability with respect to so, the upper limit on the relevant spectral integral, suggesting theoretical errors much larger than previously anticipated. We argue that this instability is due to the poor convergence of the integrated D = 2 OPE series. Alternate weight choices designed to bring this convergence under better control are shown to produce significantly improved stability, and determinations of vertical bar V-us vertical bar which are both mutually compatible, and consistent, within errors, with values obtained by other methods. (c) 2006 Elsevier B.V. All rights reserved.